Process for the alkylation of hydrocarbons



W. A. SCHULZE vJune 1,2, 1945. 2,378,040

` PROCESS Fo'n' vTHE ALKYLAfrIoN 0F mnnJRocARoNs Filed Dec. 16, 1.942

ATTORNEYS.

-ganicl syntheses.

UNITED s'm'rssv PATENT ol-Flca PnooEs's Fon. 'rim nLxm'rloN or* mmaocnanons walter A. Schulze, Bartlesville, ons., assigner Company, a Acorporation to Phillips Petroleum of Delaware Application December 1s, 1942', senci Nc.4 469,212

11 claims. `(cl. zen-sassy This invention relates to the alkylation of alkylatable hydrocarbons with low-boiling olefins inl the presence of solid or iluid alkylationcatalysts.

'I'his invention also relates to an improved method for conducting alkylation reactions of the type described whereby greater yields of higher-quality alkylatearelobtained and novel means for maintaining optimum catalyst activity and reaction conditions are provided.

It is known that the condensation of certain parafnic or aromatic hydrocarbons with olefns may be effected by noncatalytic or catalytic means to produce higher molecular weight products of great value in the manufacture of such materials as motor and aviation gasolines, fuel additives, and intermediates for many related or- The catalytic promotion of said condensation by agents such as aluminum chloride, other metal halides, strong mineral acids, certain silica-metal oxide gels and the like has been proposed, and the application of these agents to a number of reactions has been described with each particular catalyst usually exhibiting indil vidual characteristics which affect the reaction.

It is also known that reaction conditions are in many cases responsible for variations in the rate and extent of the alkylatidn reactions and, hence, in the products obtained. Thus, such factors as olen concentration, contact time, catalyst concentration and physical state, and temperature have been stated to be controlling factors in al.

kylatlon. As a result, a number of operational schemes have been suggested to control oneor another of said factors in an attempt to benefit the reaction. l

The principal difficulties encountered in the commercial application of alkylation processes of various types have been due to changes in the compositions of both hydrocarbon reactants and catalysts during the relatively long reaction pe- `riods employed. For example, the changes in the relative `concentrations of the original reactants and of several product compounds formed as re.- action proceeds and the resultant-or concurrent 'changes in catalyst activity and/or. selectivity have resulted in empirical control methods which are difficult todevelop and apply.

In the discussion to follow. the term primary reaction will be used to denote any condensation reaction involving the original hydrocarbon reactants. Similarly, the term secondary reactions will denote those involving one or more compounds other than the original reactants and may include molecular rearrangement without change combinationfof thel fragments into larger or smaller molecules. V

The complex nature of alkylation reactions is indicated by the fact that primary alkylation products are capable of entering into further combinations with the olefinic alkylating agents to an extent at least partially determined byrelative concentrations in ther eaction zone. Other factors which may affect such secondary combinations are the nature of the catalyst, the location of the alkylating agent (Whether in the hydrocarbon or the catalyst phase) and the relative ease of alkylation of the alkylatable compounds added to or formed inthe reaction zone.

`Further, the stability of the primary and/or secondary products under the alkylation conditions varies greatly, and considerable dealkylation and rearrangement often occurs, producingY compounds which can be accounted for only on the basis of the transient presence of olefins, and' saturated residuesv which were not present in the original 'reactant feed.. This rearrangement or recombination of fragments of relatively unstable products may alter the boiling range, octane vnumber and various other characteristics of the is in contact at various points in the reactiony zone.` Also, in case of` catalysts containing vol-v atile or hydrocarbon soluble components'tran'sferable to the hydrocarbon phase, a more or less progressive change in activity may be noted, either` in molecular weight, fragmentation, and/or re- ISISl during continued use of with changes, in the composition of the hydrocarbon phase during a single contact period. This is also true in the case of catalysts used with promoters which are added intermittently or continuously to the reaction zone and which are often easily transferred to and carried out by the hydrocarbons. Means of maintaining catalyst compositionsand/or activities duringtuse, are thereforeof great com- Vmercial importance in'y operations utilizing such catalysts and/ or promoters. l

It isan object of vthis invention to provide a novel process for conducting reactions `under conditions conducive to more selective and controlled combination. Another object of this invention is to provide a means of controlling the concentration of one or more reactants at chosen points in an alkyla- -tion zone to control the reactions occurring there;

u a reaction zone while permitting substantiallyY lonly secondaryreactions in' portions of said reaction zone subsequently traversed by the reaction mixture. y 1

Further objects and advantages oi my invention will become apparent from the accompanying disclosure and discussion.

I have now discovered that these objects and improvements may be accomplished by a novel method which eil'ectively divides an alkylation reaction vessel, adapted to use oi either solid contact or iluid catalysts, into two zones namely, a contact zone in which primary aikylation reac- .tions are favored and catalyst activity maintained, and a secondary or stripping zone in which secondary reactions are favored by limiting the concentration of original alkylating agent and of 'volatile catalyst components therein.l The provision of the stripping zone further aids in the recovery of volatile or hydrocarbon-soluble materials otherwise carried out by the eilluent hydrocarbon liquid, u

In one speciiic embodiment of my invention an alkylation reaction is conducted with improved control of reaction conditions and of alkylate` compositions by introducing a mixture oi catalyst and liquid isoparaflln or other alkylatable hydrocarbons at the top end of a vertically placed reac'- tion zone to travel concurrently and in a state a point above the point ofintroduction of the liquid hydrocarbon. In'addition, there is added to the reaction zone at a, point below the olefininJection port a stream oi` substantially inert v strippingy gas which likewise passes countercurrent to the descending liquid mixture and through the reaction zone to the gas exit line above the point of introductionof vthe hydrocarbon liquid. The liquid efiluent from the .reaction zone passes to 'a separating zone for settling and removal of any catalyst from the -hydrocarbon stream. 'I'he A further object of this invention is to` provide I" Figure I shows an embodiment of the invention particularly adapted to use oi' either a fluid catalyst or a solid catalyst with a iluid promoter. In this ilow diagram, liquid isoparamn or another alkylatable compound of suitable characteristics is supplied by line i to reaction vvessel I, 'shown in section. Simultaneously, fluid catalyst and/or promoter' in the proper porportions is supplied from source 2 and line l. The liquid hydrocarbon passes 4downward through contact zone 5 which may be a packed section or granular porous mass adapted to maintaining intimate contact ,between immiscible liquid phases and between gas and` The descending liquids after passing through the contact zone Buthen travel through a stripping zone lwhich may be relatively quiescent ex k cept for the agitation and stripping-action of` a substantially inert gas, such, as nitrogen, methane, etc., introduced to the bottom of the zone through line 8.l The stripped alkylate-catalyst mixture then passes through line 8 to separator III where the immiscible liquid phases may separatel and catalyst is withdrawn through line i I. This used l catalyst may be returned to the reaction vessel through I2, or may pass in some cases to scrubber Il through line i3'. In the scrubber, desirable components of gases leaving the reaction chamber through line I5 are transferred to the catalyst which then passes through line I5 for recycle to the reaction vessel. Alkylate removed from through line I1 to fractionator AIB where alkylate of proper boiling range is fractionated from un reacted or lower boiling hydrocarbons. The overhead product is returned in the f orm of liquid reilux to the reaction vessel Ithrough line I9, while liquid lalkylate is takenthrough line`20 to storage or any further desirable processing.'

In. case of asolid or solid-supported catalyst,y

the contact section 5 is packed with solid granules or particles to permit easy passage of the hydrocarbon liquid and 'ascending gaseous mixtures. The catalyst supply line may serve to introduce liquid or gaseous promoters for the reaction, with the former being separated by suitable means catalyst is returned to the top of the reactor or may pass first through a scrubber where'it contacts gases leaving the top or the reaction zone.

The hydrocarbon product is fractionated to sep f arate low-boiling hydrocarbons comprising -un reactedfeed stock which are recycled to the reaction zone.

travels through the catalyst mass, countercurrent to the oleiln-conaining stream and-stripping gas. The separating zone may be required in the case from the alkylate product. In case of a relatively volatile promoter, suitable absorbents may be sup,

cycling to the reaction vessel.

By varying the depth of the contact zone and/ or the distance between the point of olen addition andv the point of catalyst and/or isoparaifln addi-s tiongthe portion lof the reaction vessel in lwhich rapidly reacting concentrations of the primary as measured by the time required for complete reactants are present maybe controlled. Possibley criteriasfor determining the eiectiver'eaction time may be the reactivity of the particular oleiln In the stripping zone the volume and velocity the separator is taken of the inert gas may be adjusted to suppress olefin concentrations in the liquid mixture below the contact zone, and/or to accomplish a similar effect in the case of gaseous promoters or catalyst components which might otherwise be carried out in the hydrocarbon stream. y

Figure II represents an alternative flow employing a fluid-type catalyst in a reaction vessel divided into an upper contact zone and a lower stripping zone. y drocarbon feed is supplied through line 3l) and catalyst is supplied from vessel 3| and line 32 to the top section of reaction vessel 33.` The mixture descends through contact zone 34 which may be a tray type contactor, packed section or other suitablecontacting device including a mechanical agitation means. olefin-containing gas is introduced at a lower point in the contact zone through line 35' and while unabsorbed passes upward in the vessel. The liquid mixture from the bottom of the contact zone is transferred through a suit- `Y xdirectly recycled to the reactionvessel, or may pass to scrubber 42 for contact with gases leaving the reaction vessel through lines 44 and 45. Unabsorbed gases arev vented from the scrubber, while the absorbent passes through lines 43, 4I and 32 to the reaction vessel, or to other means not shown for recovery ofvaluable components.

'I'he alkylate'from separator 39 is taken through -line 46 to fractionator 41 vwhere unreacted feed components as well as other low-boiling materials are recycled to the reaction vessel through line 48. Alkylate is removed through line 49 to storage or further fractionation.

This alternate arrangement embodies a separate stripping zone whereby the stripping gas may be wholly or partially excluded from the contact zone by regulation of gas flow through lines 44 and 44A, Thus suicient gas may iiow through l 44A to maintain a desired vapor flow upward `through the contact-zone, or the section below the point of olefin introduction may ybe relatively quiescent. The Vportions of the contact zone containing suflicient concentrations of primary reactants to support rapid primary alkylation are again determined by the distance between the point of olefin addition and the point of catalystliquid hydrocarbon addition.

While capable of very broad application to alkylation reactions, the process of this invention is particularly adapted to alkylation with the lower-boiling olefins such as ethylene and propylene. Heretoforefthe use of ethylene in particular has beenrestricted because of the relatively severe conditions and highly active catalyst required, which often resulted in the production of very complex mixtures of products, with a large portion usually undesirable because of high-boiling ranges. Thus, for example, conditions effect- In this diagram, the liquidrhy- I have found that particular benefits are obtained in thepresent process by maintaining ethylene concentrations suitable for alkylation in the contact zone and stripping any unreacted ethylene more or less completely from the prodpresent process. These benefits are apparently partially attributable to the fact that the olefin .rearrangement reactions may take place.

alkylation products or those of similar boiling range are `obt/ainecl at. suitable reaction rates. Comparable results are not obtained by merely shortening the contact time, reducing the volume ofthe reaction vessel or reducing the molar proportions of olefin in the reactant feed.

While the exact reasons for theseimproved results are not known, it is believed that one factor is the restriction of the olefin alkylating agent to a definite portion of the reaction vessel and that the present process enables a better control of the concentration of alkylating agent in the zone of rapid primary combination. This is accomplished bythe stripping action at the bottom of the reaction vessel and the refluxing or absorbent action at the topof the vessel. f

Furthermore, internal hot spots or zones of excessive heat evolution due to the alkylation reaction are substantially avoided since the olefin solubility adjusts itself to the temperature at any point in the contact zone and the vapor-liquid equilibrium automatically controls the, reaction rate. This effect is of greatest importance in the use of solid catalyst beds wherein conventional heat transfer means are least effective clue to low thermal conductivity of the catalyst mass.- Moreover, by regulating the temperature of the liquid hydrocarbon reflux, additional precision in temperature control is obtained.

When the catalyst contains or is promoted with volatile components, it is important to retain said materials insofar as possible within the Contact zone, andthis is accomplished to a large extent '.by the stripping action of the ascending gas stream in the stripping zone. It may be possible in some cases to return such components to the reaction vessel via the recycled liquid feedv stock, but when these compounds are corrosive or tend to condense or solidify-at low temperatures, the operating difiiculties are often tremendously increased. Thus, the present invention provides an improvement in operating with volatile, sublimable and/or corrosive catalyst compositions, and in maintaining catalyst activity Within the contact zone.

In case the gases issuing from the reaction vessel contain materials valuable for recycling which are not absorbed by the liquid reflux, the external scrubbing operation serves to recover said mate rials and may also be a means for reactivating the catalyst. Considering a catalyst composition which enters the reaction vessel containing an effective amount of a volatile component, the eilluent catalyst may contain less than said eil'ective amount at the point of separation from the hydrocarbon alkylate. For example, a catalyst saturated with a gaseous promoter at inlet condi,- tions, may contain smaller quantities of said promoter under outlet conditions of temperature, etc. This used catalyst may be employed to scrub the vented gases to absorb and recover catalyst components carried out in the gas stream, with the conditions adjusted to produce substantially the catalyst by other means.

Although it is preferred to adjust reaction conditions to obtain substantially complete olen utilization, the scrubbing of the vented gases may also serve to recover unreacted olefin gases andreturn them to the reaction vessel. This maybe accomplished, for example, when a relatively stable catalyst-olefin solution is formed under conditions which permit its return to the reactionl vessel with recycled catalyst. This procedure may be limited to those olens which are not.

particularly susceptible to polymerization in the are useful in the alkylation reaction.

Conditions within the reaction vessel are adapt,- ed to the alkylation reaction being carried out, and particularly `to the catalyst and the alkylating agent. With catalysts such as the strong mineral acids, aluminum halides, boron fluoride complexes, and the like, relatively low temperatures of from about zero to about 200 F. are often employed, while in the alkylation. of aromatics such as benzene over solid gel-type silica-alumina catalysts, somewhat higher temperatures up to about 500 F. may be required'.1 The effect of the olen alkylating agent is usually noted in variations of the optimum temperature range which is generally lower for the higher boiling'olens.

Pressures in the process are ordinarily sufficient to maintained the isopa'railin, aromatic or other alkylatable hydrocarbon in liquid phase at the maximum operating temperatures and/or lto alfto provide molar proportions of isoparaflin or other alkylatable hydrocarbon substantially in r excess of the olefin alkylating agent. The selection of ratios of these reactants in the total fresh feed will ordinarily be above about 1:1 and may be 4:1, or higher. Recycle of unreacted alkylatable hydrocarbon, as through conduit I9, will in- 'crease the ratios somewhat in the total charge to.

the contact zone.

eiiluentfor conventional separation of catalyst, alkylateand any unreacted ethylene, considerable loss of boron uoride in the lhydrocarbon phase is experienced, 'and 60-'70 per cent lof the butane-free alkylate boilsabove and below the hexane range.. f

y When `the reaction is carried out according to the present invention. ethylene gas is injected at about the mid-point of a contact section of the i vertical reaction vessel, said section being packed with carbonI rings to give intimate contact between catalyst, isobutane and ethylene. The liquid catalyst and liquid isobutane `are added in a volume ratio of about 1:2 to the reaction vessel Apresence of said catalyst, or whose lower polymers in a free space above the pacled section. Sunicient ethylene is added to result in an isobutaneethylene molar ratio in the total feed vof 4:1 based f lon the isobutane feedrate.

i the stripping is accomplished `by methane gas injected at the bottom of the vessel. The stripped eilluent hydrocarbons after settling and separal tion from the catalyst contain little boron uoride Specic examples are provided hereinafter to illustrate applications of the present invention to typical alkylation reactions. However, since,the number of such examples might be greatly multiplied, no limitation of the process is implied.

Example I Isobutanemay be alkylated'with ethylene in the presence of a catalyst prepared by saturating water with boron fluoride to `form a liquid hydrate composition. The reaction in the presence `of this hydrate catalyst is favorable to the formation `of normally liquid isoparamns, having high octanevnumbers, at temperatures of .about 10U-130 F., and pressures of 10U-300 pounds gage. l In carrying out the` reaction in mechanically stirred reaction vessels and removing the total or ethylene and hence these gases are present in negligible amounts in the overhead of the alkylate fractionator. The ascending gas stream entering the contact zone consists of methane, ,boron fluoride and ethylene, while the gas stream leaving the contact zone consists principally of methane with some boron fluoride. The gases are vented through a pressure release valve and a,

scrubber wherein the boron fluoride. is absorbed at lowered temperature in used catalyst. f

In this scheme of operation, boron fluoride con- .sumption per gallon of alkylate, catalyst dilution with `heavy hydrocarbons and ethylene removal Example `11 In. the alkylation of isobutane with ethylene over a solid catalyst consisting of bauxite im-` pregnated with aluminum chloride and a minor amount of hydrogen chloride, liquid isobutane is passed downward through a bed of the granular catalyst, while gaseous ethylene is introduced near the bottom of the catalyst mass and while un- `absorbed passes upward countercurrent to the liquid isobutane. The liquid alkylate ows downward from the'catalyst bed' through a stripping zone countercurrent to an ascending stream of Ci-Cs gas which removes from the hydrocarbon liquid and carries upward into the catalyst bed unreacted ethylene and traces of hydrogen chloride. IThe strippin'ggas vented from the reaction vessel at a point above the point of isobutane introduction contains only traces of ethylene zwhen the isobutane-ethylene molar ratiois about 4:1, and the contact time based on liquid isobutane feed rate is 30-40 minutes. The catalyst activity is maintained' over long periods without additions of promoter. i

Y y Example II In the alkylation of benzene with ethylene over granular silica-alumina gel, at a temperature of 490 F. and l1500 pounds 'gage pressure, benzene feed is added at the top of a bed of catalyst while ethylene is added to the lower section of the catav l lyst mass ina benzene-ethylene molar ratio of 6:1`F The liquid products pass from the bottom ofthe catalystfzone through a` stripping zone where ethylene is removed and returned by an ascending stream of methane gas to the catalyst Ezranipley IV In alkylating isopentane with propylene in the presence of a liquid catalyst containing boron fluoride-phosphoric acid addition complex, the

reaction zone an alkylation catalyst and alkylat- I ing conditions such that said allrylatable hydro- K kcarbon remains primarily in liquid phase during its passage down said reaction zone and such that a gas phase is also present in said reaction zone, passing liquid eiliuents from the bottomv of apparatus of Figure 1 is employed to produce Cs-Cm isoparaiTlns having high octane numbers and substantially i'ree of olefin polymer. The liquid isopentane and catalyst are supplied' to the top of a contact zone packed with carbon rings, and propylene is added at a point about midway oi the contact zone in proportions to give an isopentane-propylene molar ratio of 4: 1. The liquid mixture passes from the contact zone through a relatively quiescent zone countercurrent to an ascending stream of propane gas. 'I'he propane strips dissolved propylene and boron fluoride from the liquid hydrocarbons, and returns these components to the contact zone.

' Catalyst and hydrocarbons are separated in a settling zone, with the latter. being fractionated to separate isopentane for recycling to the reaction. Used catalyst may be partially recycled direct to the reaction vessel, while a portion is uoride from the gas stream vented from the top of the reaction vessel. In this system, the recovery of boron iiuoride may be sufliciently complete to eliminate regular additionsof boron fluoride to resaturate the catalyst.

The alkylate when compared with that pro- Y duced by premixing the reactants contains substantially increased proportions of isoparaiiins suitable for blending in aviation fuels, and a particular improvement in octane rating is obtained. f

It will be appreciated-that various modifica-Y tions may be practiced by one skilled in the art without departing from the spirit of the teachings or fronrthe scope of the claims.

I claim:

1. A process for producing low-boiling nor-v mally liquid paraffin hydrocarbons by alkylatinggas to vaporize said dissolved gaseous con- `stituents, passing a resulting gaseous mixture from said stripping zone to the bottom of said alkylation zone, and withdrawing `from said stripping zone a hydrocarbon mixture alkylate so produced.

2. A process for alkylating hydrocarbons containing which comprises introducing a liquidalkylatable hydrocarbon tothe top of a 4reaction zone, introducing a gaseous alkylating agent to the bottom of said reaction zone, maintaining inv said '30 cooled to 20-40"v F. and used to absorb boronv said reaction zone to the top of a stripping zone, maintaining in said reaction zone alkylation reaction conditions and a; flow of reactants such that said liquid eiilents contain dissolved unreacted alkylating agent, introducing an inert stripping gas to the bottom of said stripping zone and passing same upwardly 'through said stripping zone countercurrent-to liquid eiiluents of said reaction zone to remove in vapor form volatile impurities vtherefrom including said dissolved alkylating agent, removing from the bottom'of said stripping zone a purified valkylation eliiuent, removing from the top of said stripping zone said stripping gas and gaseous impurities removed from said liquid reaction zone eflluents, passing said gas to the bottom of said reaction zone to deliver said impurities to said reaction zone, and finally removing from the top of said reaction zone said stripping gas.

3. The process of claim 2 in which said alkylation catalyst comprises boron fluoride and in which liquid effluents of said reaction zone contain uncombined boron fluoride vas an impurity, said boron fluoride also being removed in said stripping zone as a gas and returned lto said reaction zone in the gas passed from the top of said stripping zone to the bottom of said reaction zone.

4. 'Ihe process o! claim 2 in which said alkylation catalyst comprises a complex of Water and boron fluoride and in which boron Ai'luoride is removed in said liquid eiiiuents of said reaction zone as said impurity.

5. The process ofclaim 2 in which said alkylation catalyst comprises a complex of an acid of phosphorus and boroniiuoride and in which boron uoride is removed in said liquid eiliuents of said reaction zone as said impurity.

6., A process for' alkylating hydrocarbons, which comprises introducing a, liquid alkylatable hydrocarbon to the top of a reaction zone, introducing a vaporizable alkylating agent to the bottom of said reaction zone, maintaining in said reaction zone an alkylation catalyst comprising a complex of boron fluoride and an acid of phosphorus and alkylating conditions such that 'said alkylatable hydrocarbon remains primarily in liquid phase during its` passage down said reaction zone andV such that a gas phase comprising an inert stripping gas and also said Vaporizable alkylatingagent is also present in said zone, passing liquid effluents containing dissolved boron fluoride` and unreacted vaporizable alkylating agent as impurities from the bottom of said reaction zone vto a stripping zone, introducing to said stripping zone an inert stripping gas, conl tacting said eiliuents in said stripping zone with liquid mixture in said stripping zone an inert said stripping gas to remove boron iiuoride and vaporizable alkylating agent as gases, removing purified liquid reaction zone eiiluents from said stripping zone, passing a gas comprising said stripping gas andv boron fluoride .and vaporizable alkylating agent from said stripping-.zone to the bottom of said reaction zone, passing from the top oi` said reaction zone a. gas'comprising said stripping gas and a minor amount of boron uoride,'contacting the last said gas with'a,

liquid `acid of phosphorus to absorb said boron fluoride, and passing a resulting liquid boron fluoride-acid of phosphorus mixture to said re-` action zone as atgleast a part of said alkylation catalyst.

7. -The process of claim 6 in which said alkyl- Patent No. '2,578,0llo

IwAL'rER li.v SCHULZE.

and said catalyst complex downward through a catalytic alkylation zone. adding near theV bottom of said zone a gaseous olefin, withdr'aylzing `from 'the bottom of said allqlation `zone an efatable hydrocarbon is isopentane and said alkyluent liquid mixture comprising catalyst, and ating agent is a normally gaseous olefin. hydrocarbons and containing in solution said 8. 4'I'he processor claim 2 in which said alkyl- I normally gaseous catalyst constituent and unatable hydrocarbon is a butane, said alkylating reacted gaseous olen and passingsame to a agent is ethylene, andvsaid catalyst comprises stripping' zone, paming through said eilluent aluminum chloride and hydrogen chloride. 10 liquidmixture in said stripping zone an inert 9. A process for producing low-boiling norgas to vaporize saidrdissolved gaseous conmally liquid parailin hydrocarbons by alkylating. stituents, passing a resulting gaseous mixture isobutane with ethylene'in the presence of a from said stripping zone to the bottom ofv said liquid catalyst complex resulting from saturating alkylation zone, and withdrawing from said water with boron triuoride and containing at stripping zone a hydrocarbon mixture containing least a minor amount of free boron triiluoride, allLvlate so producedand a liquid catalyst mixwhich comprises passing a' liquid mixture of ture, passing a gaseous mixture'subs'tantially free isobutane andv said complex downward through of oleflns and comprising said ine'rt gasand said a catalytic alkylation zone, adding near the botnormally gaseous catalyst constituent from the tom of said zone gaseous ethylene, withdrawing top of said alkylation zone to a scrubber, passing from the bottom oisaid alkylation zone -an efa portion of said liquid catalyst mixture from iiuent liquid mixture comprising catalyst and said stripping zone-to said scrubber to` absorb hydrocarbons, and containing fin solutionfree said gaseous catalyst constituent, and passing boron trluoridevand unreacted ethylene and the resulting liquid catalyst mixture from said passing same to a stripping zone, passing through `scrul; er to the'top oi said alkylation zone. 1 said eiliuent liquid mixture in said stripping zone 11K-2A process for producing low-'boiling noran inert gas to `vaporize said dissolved boron trimally liquid paraln hydrocarbons by alkylating iluoride and ethylene, passing aresulting gaseous .i'isobutane with ethylene in the presence of a mixture from said stripping zone -to the bottom v liquid catalyst complex resulting from saturating of said alkylation zone, and withdrawing from Water with boron trifluoride and containing at said stripping zone a hydrocarbon mixture conlleast a minor amount of free borontriuoride, taining normally liquid paraffin hydrocarbons so which comprises passing a liquidmixture of iso-l produced and a liquid catalyst mixture, passing butane and said complex downward through a a gaseousrnixture substantially free .of olens A catalytic alkylationzone, adding near`the botand containing free boron triiluoride from the 35 tom` of lsaid zone'gaseous ethylene, withdrawing top of said alkylation zone to a scrubber, passfrom the bottom of said alkylation zone an efing a portion of said liquid catalyst mixture from fluent lliquid. mixture `comprising catalyst andl said stripping zone to said scrubber to remove hydrocarbons, and containing. in solution free boron trifluoride -from the last said gaseous mixboron triiluoride and -unreacted ethylene .and ture, and passing the resulting liquid, boron passing same toastripping. zone, passing through .triiluoride-containing catalyst from' said scrubsaid elilunt liquid mixture insaidA strippingzone ber to the top of said alkylation zone. an inert gas to vaporize said dissolved boron 10". A process for producing low-boiling. nortriuoride and ethylene, passing a resulting lmally liquid parailln hydrocarbons by alkylating gaseous mixture from said stripping zone to the -a low-boiling alkylatable hydrocarbon with a 5 bottom of said alkylation zone, and withdrawnormallyv gaseous` olefin in the presence of a ing from said stripping zone a hydrocarbon mixliquid catalyst complex comprising a normally ture containing normally liquid parailin hydrogaseous constituent, which comprises passing a carbons so produced. l liquid mixture .of said alkylatable hydrocarbon WALTER. A. SCHULZE.

Jane 12, 19h13.

. .[t is hereby certified n"thank,'error appears in the printed specification of the ahoverrumbered patent requiring correction as follows: Page 1`, second column,` `line 8, for "ther onction" read the reaction-7; line 141+; .for nusecf" read--use or; Apage 2 'second column, line 52, for "1 ine l8" read --line 9";

line 55, for "maintained" read --rmainta'n--g line 56, after "through" insert finas-;`

page ll,..fi.rstco1umn, and that the said Letters Patent should be read with this correction therein that the samex'm'ay conform to therecord of the .case in the Patent? Office,

Signedy and sealed this 116th 'day off pctober, A. D.` 1914.5.

(Seal.)

V llleslie Frazer First Assistant `Commissioner if yPatents'. A.

fluoride-acid of phosphorus mixture to said re-` action zone as atgleast a part of said alkylation catalyst.

7. -The process of claim 6 in which said alkyl- Patent No. '2,578,0llo

IwAL'rER li.v SCHULZE.

and said catalyst complex downward through a catalytic alkylation zone. adding near theV bottom of said zone a gaseous olefin, withdr'aylzing `from 'the bottom of said allqlation `zone an efatable hydrocarbon is isopentane and said alkyluent liquid mixture comprising catalyst, and ating agent is a normally gaseous olefin. hydrocarbons and containing in solution said 8. 4'I'he processor claim 2 in which said alkyl- I normally gaseous catalyst constituent and unatable hydrocarbon is a butane, said alkylating reacted gaseous olen and passingsame to a agent is ethylene, andvsaid catalyst comprises stripping' zone, paming through said eilluent aluminum chloride and hydrogen chloride. 10 liquidmixture in said stripping zone an inert 9. A process for producing low-boiling norgas to vaporize saidrdissolved gaseous conmally liquid parailin hydrocarbons by alkylating. stituents, passing a resulting gaseous mixture isobutane with ethylene'in the presence of a from said stripping zone to the bottom ofv said liquid catalyst complex resulting from saturating alkylation zone, and withdrawing from said water with boron triuoride and containing at stripping zone a hydrocarbon mixture containing least a minor amount of free boron triiluoride, allLvlate so producedand a liquid catalyst mixwhich comprises passing a' liquid mixture of ture, passing a gaseous mixture'subs'tantially free isobutane andv said complex downward through of oleflns and comprising said ine'rt gasand said a catalytic alkylation zone, adding near the botnormally gaseous catalyst constituent from the tom of said zone gaseous ethylene, withdrawing top of said alkylation zone to a scrubber, passing from the bottom oisaid alkylation zone -an efa portion of said liquid catalyst mixture from iiuent liquid mixture comprising catalyst and said stripping zone-to said scrubber to` absorb hydrocarbons, and containing fin solutionfree said gaseous catalyst constituent, and passing boron trluoridevand unreacted ethylene and the resulting liquid catalyst mixture from said passing same to a stripping zone, passing through `scrul; er to the'top oi said alkylation zone. 1 said eiliuent liquid mixture in said stripping zone 11K-2A process for producing low-'boiling noran inert gas to `vaporize said dissolved boron trimally liquid paraln hydrocarbons by alkylating iluoride and ethylene, passing aresulting gaseous .i'isobutane with ethylene in the presence of a mixture from said stripping zone -to the bottom v liquid catalyst complex resulting from saturating of said alkylation zone, and withdrawing from Water with boron trifluoride and containing at said stripping zone a hydrocarbon mixture conlleast a minor amount of free borontriuoride, taining normally liquid paraffin hydrocarbons so which comprises passing a liquidmixture of iso-l produced and a liquid catalyst mixture, passing butane and said complex downward through a a gaseousrnixture substantially free .of olens A catalytic alkylationzone, adding near`the botand containing free boron triiluoride from the 35 tom` of lsaid zone'gaseous ethylene, withdrawing top of said alkylation zone to a scrubber, passfrom the bottom of said alkylation zone an efing a portion of said liquid catalyst mixture from fluent lliquid. mixture `comprising catalyst andl said stripping zone to said scrubber to remove hydrocarbons, and containing. in solution free boron trifluoride -from the last said gaseous mixboron triiluoride and -unreacted ethylene .and ture, and passing the resulting liquid, boron passing same toastripping. zone, passing through .triiluoride-containing catalyst from' said scrubsaid elilunt liquid mixture insaidA strippingzone ber to the top of said alkylation zone. an inert gas to vaporize said dissolved boron 10". A process for producing low-boiling. nortriuoride and ethylene, passing a resulting lmally liquid parailln hydrocarbons by alkylating gaseous mixture from said stripping zone to the -a low-boiling alkylatable hydrocarbon with a 5 bottom of said alkylation zone, and withdrawnormallyv gaseous` olefin in the presence of a ing from said stripping zone a hydrocarbon mixliquid catalyst complex comprising a normally ture containing normally liquid parailin hydrogaseous constituent, which comprises passing a carbons so produced. l liquid mixture .of said alkylatable hydrocarbon WALTER. A. SCHULZE.

Jane 12, 19h13.

. .[t is hereby certified n"thank,'error appears in the printed specification of the ahoverrumbered patent requiring correction as follows: Page 1`, second column,` `line 8, for "ther onction" read the reaction-7; line 141+; .for nusecf" read--use or; Apage 2 'second column, line 52, for "1 ine l8" read --line 9";

line 55, for "maintained" read --rmainta'n--g line 56, after "through" insert finas-;`

page ll,..fi.rstco1umn, and that the said Letters Patent should be read with this correction therein that the samex'm'ay conform to therecord of the .case in the Patent? Office,

Signedy and sealed this 116th 'day off pctober, A. D.` 1914.5.

(Seal.)

V llleslie Frazer First Assistant `Commissioner if yPatents'. A. 

